A conventional abnormality detection apparatus for an exhaust gas recirculation apparatus for a naturally aspirated engine that includes an EGR passage that connects an intake passage and an exhaust passage, and an EGR valve that is responsible for opening and closing the EGR passage is disclosed, for example, in Patent Document 1. According to the aforementioned conventional abnormality detection apparatus, after calculating an estimated value of an intake pressure based on at least a degree of throttle opening, a degree of EGR valve opening, and a engine speed and the like, an abnormality of an EGR apparatus is detected based on a difference between an actual intake pressure detected by an intake air pressure sensor and the estimated intake pressure.